This invention relates to a synchronous circuit used for coinciding an external video signal from, for example, a laser disc, in synchronization with a video signal generated by an internal computer.
Generally, game machines or the like use the external video signals from the laser disc or the like and the internal video signals generated by the computer, in which images, as well-known, are turbulent unless both these signals perfectly coincide with each other.
Conventionally, in order to synchronize such both signals with each other, for example, a PLL (phase-locked-loop): the so-called phase synchronous circuit following-up phase of input signal, has been used, which is defective in that it takes much time to synchronize such circuit.